Exam 19: The First Law of Thermodynamics

An ideal gas with γ = 1.30 occupies 7.0 L at 300 K and 200 kPa pressure.It is compressed adiabatically to 1/7 of its original volume,then cooled at constant volume to 300 K,and finally allowed to expand isothermally to 7.0 L.How much work does the gas do during this process? The ideal gas constant is R = 8.314 J/mol • K = 0.0821 L • atm/mol • K.

When a fixed amount of ideal gas goes through an isothermal expansion,

A container of ideal gas has a movable frictionless piston.This container is placed in a very large water bath and slowly compressed so that the temperature of the gas remains constant and equal to the temperature of the water.Which of the following statements about this gas are true for this process? (There may be more than one correct choice.)

An expansion process on an ideal diatomic gas has a linear path between the initial and final states on a pV diagram.The initial pressure is the initial volume is and the initial temperature is The final pressure is and the final temperature is The change in the internal (thermal)energy of the gas is closest to

During an adiabatic process,20 moles of a monatomic ideal gas undergo a temperature change from 450 K to 320 K starting from an initial pressure is 400 kPa.The ideal gas constant is . (a)What is the final volume of the gas? (b)How much heat does the gas exchange during this process? (c)What is the change in the internal (thermal)energy of the gas during this process?

The temperature of an ideal gas in a sealed 0.40- rigid container is reduced from 350 K to The final pressure of the gas is The molar heat capacity at constant volume of the gas is 28.0 J/mol • K.The heat absorbed by the gas is closest to

An ideal gas with γ = 1.67 is initially at 0°C in a volume of 10.0 L at a pressure of 1.00 atm.It is then expanded adiabatically to a volume of 10.4 L.What is the final temperature of the gas?

A monatomic ideal gas undergoes an isothermal expansion at 300 K,as the volume increased from to The final pressure of the gas is The ideal gas constant is .The change in the internal (thermal)energy of the gas is closest to

The figure shows a pV diagram for 4.3 g of oxygen gas (O₂)in a sealed container.The temperature T₁ of the gas in state 1 is 21°C.What are the temperatures T₃ and T₄ of the gas in states 3 and 4? The ideal gas constant is R = 8.314 J/mol • K = 0.0821 L ∙ atm/mol • K,and the ATOMIC weight of oxygen is 16 g/mol.

The gas in a perfectly insulated system does work at a rate of At what rate is the internal (thermal)energy of the gas changing?

A system has a heat source supplying heat to an ideal gas at a rate of 187.0 W and the gas is doing work at a rate of 130.9 W.At what rate is the internal (thermal)energy of the gas changing?

A compression,at a constant pressure of 190 kPa,is performed on 5.0 moles of an ideal monatomic gas.The compression reduces the volume of the gas from to The ideal gas constant is R = 8.314 J/mol • K. The work done by the gas is closest to

A fixed amount of ideal gas goes through a process abc.In state a,the temperature of the gas is 152°C,its pressure is 1.25 atm,and it occupies a volume of 0.250 m³.It then undergoes an isothermal expansion to state b that doubles its volume,followed by an isobaric compression back to its original volume at state c.(Hint: First show this process on a pV diagram.)The ideal gas constant is ,and . (a)How many moles does this gas contain? (b)What is the change in the internal energy of the gas between states a and b? (c)What is the net work done on (or by)this gas during the entire process? (d)What is the temperature of the gas in state c?

During an isothermal process,5.0 J of heat is removed from an ideal gas.How much work does the gas do during this process?

When a fixed amount of ideal gas goes through an adiabatic expansion,

In a thermodynamic process involving 7.8 moles of an ideal gas,the gas is at an initial temperature of 24°C and has an initial volume of 0.040 m³.The gas expands adiabatically to a volume of 0.080 m³.For this gas,C_V = 12.27 J/mol • K,and the ideal gas constant is .Calculate the work done by the gas during this expansion.

A monatomic ideal gas undergoes an isothermal expansion at 300 K,as the volume increased from to The final pressure is The ideal gas constant is .The heat transfer to the gas is closest to

An ideal gas increases in temperature from 22°C to 42°C by two different processes.In one process,the temperature increases at constant volume,and in the other process the temperature increases at constant pressure.Which of the following statements about this gas are correct? (There may be more than one correct choice.)

3.0 moles of an ideal gas with a molar heat capacity at constant volume of 4.9 cal/(mol • K)and a molar heat capacity at constant pressure of 6.9 cal/(mol • K)starts at 300 K and is heated at constant pressure to 320 K,then cooled at constant volume to its original temperature.How much heat flows into the gas during this two-step process?

A cylinder contains 1.2 moles of ideal gas,initially at a temperature of 116°C.The cylinder is provided with a frictionless piston,which maintains a constant pressure of on the gas.The gas is cooled until its temperature has decreased to For the gas and the ideal gas constant (a)Find the work done by (or on)the gas during this process.Is the work done by or on the gas? (b)What is the change in the internal (thermal)energy of the gas during this process? (c)How much heat is transferred to (or from)the gas during this process? Does this heat flow into or out of the gas?